The mustaches, goatee and horns Mr. Burns draws on the monitor over Marge's head disappear when the view zooms out.
During the Jack Marley retirement party, Homer and Marge are dressed up throughout however in one shot when Smither's announces that he's prepared a musical number for Jack's special night, they are suddenly wearing their normal clothes and have swapped places.
Homer's hat changes from red to blue in two shots.
The animal handler on Krusty's show is missing her glove in one shot.
At the beginning of the wrestling match between the wolf and Groundskeeper Willie he tears off his shirt, but then later during the fight the shirt is back on.
Lisa says both Marie Curie and Pierre Curie died of radiation poisoning. While this is what happened to Madame Curie, Monsieur Curie was killed when he was run over by a cart. This is one goof the writers admitted to greatly regret.
When Marge types up her resume, she only states that she was a housewife. Resumes are supposed to list education and declare what job an applicant is submitting for. It's an understandable mistake for someone who hasn't applied for a job before, like Marge, to make.